I'm on the moderation side of this topic. I've got three piercings, two in my left ear and one in my right; I had a second in my right ear, but it was too far forward so I let it close up. I'm getting it redone for my birthday. May or may not get a third set in my ears; that'd be my max, and it depends on how things look in about a year. Belly button piercings are kind of cool, and I'd kind of like to get one. Beyond those? ONE eyebrow piercing looks nice, but the rest of the piercings is over doing it and gross, IMO. And I don't get gauged ears; again, they look gross when you put those huge plugs in.
Tattoos? Depends on how their done. Small and minimalist is my opinion. And because the ink is pretty much permanent, you want to be careful about what you get, cause it's gonna last unless you have laser removal or something like that. I'm thinking about getting one in a couple years; right now, I've got a couple goals I want to reach first. But it'd be small, probably black or dark blue, and on my shoulder.